Why I publish Project Euler solutions
There's a debate in the Project Euler community about whether people should publish their solutions to the problems. The official website has a policy of not allowing solutions to be posted or discussed, other than on the forum, with the exception of the first 100 problems.
I think this policy is overly restrictive, especially as the problems get harder. As with Advent of Code, often a single comment from someone discussing a solution can provide the missing link to something which has been stopping me from moving forwards. Sharing knowledge and insights is important - Euler himself published over 800 papers and generated 81 volumes of correspondence with fellow mathematicians.
As well as solving the problem itself, my solutions often demonstrate issues which are specific to the C language, such as integer overflows.
The one thing I don't do is publish the answers - you'll have to compile and run my solutions yourself.